Possible mechanisms for nonlinear de Haas-van Alphen oscillations in heavy fermion compounds

Abstract

Three possible many-body mechanisms giving rise to de Haas-van Alphen oscillations with frequencies that correspond to linear combinations of ordinary closed orbits of the Fermi surface are discussed in the context of heavy-fermion systems. The mechanisms are: (i) magnetic breakdown across the Kondo hybridization gap (magnetically induced tunneling), (ii) the strong nonlinear dependence of the heavy-fermion magnetization of the magnetic field may give rise to frequency mixing (Shoenberg effect), and (iii) the incipient antiferromagnetic order in many heavy-fermion compounds at low T provides a nonlinear coupling mechanism via modulation of the antiferromagnetic order parameter. The latter should be very effective in weak antiferromagnets.